Mysterious Foam Causes Concern among Okinawa Citizens

Ginowan, Okinawa Pref., March 16 (Jiji Press)–People in Okinawa Prefecture are increasingly concerned over a series of cases in which mysterious white foam appeared from manholes near U.S. military facilities in the southernmost Japan prefecture. A civic group has asked the U.S. military to agree on conducting on-site investigations of U.S. bases for possible leaks of per- and polyfluoroalkyl substances (PFAS), organic fluorine compounds suspected of damaging human health. But the military has refused to accept the request, and how the foam was generated remains unknown. In January, white foam appeared from a sewer manhole near the U.S. Marine Corps’ Futenma air station in the Okinawa city of Ginowan. Eyewitnesses said the foam rose to knee height and then flowed along the slope of the road. Wastewater from the base and nearby houses flow into the manhole. Unidentified foam was also spotted at a different manhole near the Futenma base in late February. The civic group took a sample of the foam spotted in January and asked Kyoto Prefectural University professor Koji Harada for analysis, finding 268 nanograms of PFAS per liter, more than five times the government-set limit of 50 nanograms. The Ginowan city government and the U.S. military conducted a survey of sewage in the manhole in January, but did not find PFAS levels exceeding the ceiling. The U.S. military also said that it does not currently use fire extinguishers containing PFAS. PFAS compounds, which repel water and oil, and are resistant to heat, were once used for various products, including firefighting foam and coatings for frying pans. But they are suspected of increasing cholesterol levels, and causing cancer and immunotoxicity. Production and imports of PFOS and PFOA, both PFAS compounds, were banned in Japan in principle in 2010 and 2021, respectively. Similar incidents involving mysterious foam happened in the past. In April 2020, white foam from the Futenma base flew to a nearby river. The U.S. military investigated the foam and admitted a leakage of fire extinguishing agents containing PFAS. In response to growing international concern over PFAS, the Okinawa prefectural government has been conducting surveys on the quality of river water and groundwater since 2016. With high levels of PFAS often detected around U.S. bases, the Okinawa side has called for investigations inside the bases. But the U.S. military has refused to cooperate, saying that there is no evidence showing contamination originating from U.S. bases. In October 2025, local residents asked a prefectural council on mediation related to pollution for on-site investigations of U.S. bases. But the council turned down the request, saying that defense-related facilities are not subject to mediation. Chiemi Yonashiro, a 53-year-old resident of Ginowan, who saw the foam in January, said, “I thought it was PFAS, like in past cases.” “I’m worried that children might accidentally touch it,” Yonashiro said. END [Copyright The Jiji Press, Ltd.]